It's not just the Great Lakes. We had to build canals to make those navigable. The excessive network of navigable rivers, and barrier islands that connect Corpus Christi, TX with Baltimore, MD, should make everything east of The Mississippi River blue, and most of the western half of the Continental states are within a couple hundred miles of a naturally navigable river. We may have more naturally navigable rivers than the rest of the world combined.

Jesse: Michigan is a landlocked state.

Walter: The Great Lakes State?

Jesse: I mean, sure it is made up of two peninsulas and a bunch of islands,
And It has the largest navigable international border in the US,
And the Great Lakes feed into the ocean through the St Lawrence Seaway, And millions of tonnes of cargo pass through the Great Lakes each year on oceangoing vessels.
But it technically does not have a border touching the ocean. That means it’s landlocked.

Walter: Jesse, WTF are you talking about?

The Mississippi River is also navigable for barges all the way up through Minnesota